This is a continuation from yesterdays post.

Now what is the impact of comments on the speed of JavaScript execution, beyond the obvious overhead at download and parse time?

Comment Tests

In this test 500000 iterations of the main function are performed. The number of comments varies from 1 to 200 in increments of 13. Each of the comments is 64 characters long

In this test 500000 iterations of the main function are performed. The number of comments varies from 1 to 3000 in increments of 200. Each of the comments is 64 characters long

Looks like comments have absolutely no effects at run-time. Looks like they must be removed at parse time.

Whitespace Tests

In this test 500000 iterations of the main function are performed. The number of whitespace characters varies from 1 to 15000 in increments of 1000.

Looks like whitespace is irrelevant as well.

Conclusions

You can comment and pad your code with whitespace as much as you like, all you are going to affect is the load and parse time. Execution time will not be effected. When it comes down to it, there are lots of tools that will 'compress' your JavaScript and remove comments and excess whitespace.